This invention relates to a vapor assisted fuel dispensing nozzle of the general type disclosed in U.S. Pat. No. 5,832,970. In such a nozzle, a nozzle body defines a fuel supply passage, and a normally closed main control valve is actuated by a lever pivotally supported by the nozzle body for controlling the supply of fuel through the fuel supply passage. The lever is protected by a guard member secured to the body, and the actuating lever carries a latch or trigger member which is pivotally supported by a cross pin. The trigger member has an outer end portion adapted to engage a catch or stop member supported by the guard member, and a spring member biases the trigger member towards the lever. Actuation of the trigger member functions to hold the actuating lever and the fuel supply valve in their open positions until the nozzle spout detects the presence of fuel and automatically lifts the lever to release the trigger member and permit the lever and fuel supply valve to return to their normally closed positions.
As disclosed in the above ""970 patent, the latch or trigger member 78 is biased against a stop on the actuating lever 60 by a conventional sheet metal leaf spring 84 which extends above the pivot pin for the latch or trigger member 78. Such a sheet metal leaf spring has been used for over 30 years and is disclosed, for example, in U.S. Pat. No. 3,653,415, U.S. Pat. No. 3,817,285, U.S. Pat. No. 4,022,235 and U.S. Pat. No. 5,289,856. After a fuel dispensing nozzle has been used for filling fuel tanks with an automatic shut-off of the valve actuating lever for approximately 100,000 times, it has been found that the leaf spring fatigues and fails by weakening and/or breaking. This requires that the nozzle be serviced by removing the trigger member and replacing the leaf spring. Frequently, the leaf spring is one of the first components to fail, which usually requires that the fuel dispensing nozzle be removed from the fuel supply hose and shipped back to the nozzle manufacturer or rebuilder to replace the leaf spring.
The present invention is directed to a fuel dispensing nozzle of the type described above and which incorporates an improvement for significantly extending the service life of the nozzle before requiring replacement or rebuilding. The improvement comprises replacing the conventional leaf spring for actuating the latch or trigger member with a formed wire coil torsion spring having a plurality of turns mounted on the pivot pin for the latch or trigger member. The wire coil spring has opposite end portions which engage the valve actuating lever and the trigger member.
Other features and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.